Brake



Nov. 18,- 1941. R. A. GOEPFRICH BRAKE Filed March 19, 1938 I INVE E000 6260:7/2/0/ BY 5 I ATTORNEY.

Patented Nov. 18, 1941 BRAKE Rudolph, A. Goepfrich, South Bend, Ind, assignor to Bendix Products Corporation, South Bend, Ind., a corporation of Indiana Application March 19, 1938, Serial No. 196,815

(Cl. 188--l52) 8 Claims.

This invention relates to braking systems for motor vehicles. 1

An object of the invention is to provide a vacuum power operated braking system having means for maintaining the brakes in applied position.

Another object of the invention is to provide a vacuum power operated braking system for a tractor and a trailer having means connected in the system, operative substantially simultaneously with a braking operation, when the tractor and the trailer are ascending an incline, to retain the brakes in applied position.

Other objects of the invention will appear from the following description taken in connection with the drawing forming a part of this specification, and in which the drawing is a comprehensive view, largely in diagram and partly in section, illustrating a braking system embodying the invention.

Referring to the drawing, I represents a rockable cross-shaft having thereon two pairs of arms I2 and I4, one pair connected as by rods I6 to brakes I8 associated with the front wheels of a vehicle, and the other pair connected as by rods 20 to brakes 22 associated with the rear wheels of the vehicle. Correspondingly, a crossshaft 24rockable on the frame of a trailer, normally coupled to the vehicle, has thereon a pair of arms 26 connected as by rod 28 to brakes 30 associated with the rear wheels of the trailer.

The brakes may be of any preferred type. As shown, each of the brakes includes a fixed support or backing plate 32 adapted to be secured to an axle or to an axle housing, a drum 34 associated with the backing plate and adapted to be secured to a wheel, a pair of corresponding fricshaft 24.

tion elements or shoes 36 pivoted on the backing plate, a retractile spring 38 connecting the shoes, and a cam 40 mounted on the backing plate between the shoes and connected through an operating lever 42 to a conventional tension rod.

' The rockable shaft I0 has thereon an arm 44 connected as by a rod 46, a valve 54, and a rod 46a to a brake pedal lever 48 associated with a clutch pedal lever 50. The rod 461: is connected to the brake pedallqrer 48 by a connection 52, andinterposed in the connection between arm 44 of shaft I0 and the brake pedal lever 48 is a control valve 54 including a cylinder 56 having spaced ports 58 and 60, an opening 62 forventing the cylinder to the atmosphere, and a piston 64 in the cylinder.

An internal combustion engine 66 of conventional type has an intake manifold connected to the port 58 of the valve housing 56 by a conduit I0 having interposed therein a cutout valve I2, and provided intermediate the control valves 54 and I2 with branch conduits I4 and I6. The portion of the conduit I0 adjacent'to the valve 56 is flexible so that the valve may move with the The port 60 in the cylinder 56 of the control valve 54 is connected by a conduit I02 to' the cylinder of the vacuum power motor I8 back of the piston therein, and interposed in the conduit I02 is an electrically controlled valve I04 preferably actuated by a solenoid I06 connected in an electrical circuit I08 including a battery IIO, a gravity switch I I2, and a make-and-break for the circuit consisting of a contact II4 arranged for cooperation with a contactor II6 carried on the clutch pedal lever 50. The portion of the conduit I 02 adjacent to valve 56 is flexible so that the valve may be moved as stated above.

The conduit I02 has a branch 1 I8, intermedi ate the electrically controlled valve,I04 and the vacuum power motor I8, connected through a relay valve I 20 to'the cylinder 92 of the vacuum power motor back of the piston 96, and the relay valve is connected by a conduit I22 to the conduit I6 so as to by-pass the vacuum power motor 90. r

In operation, assuming that the system is at rest with the brakes of the tractor and the trailer in the ofi or retracted position and thatthe engine is operating-under normal load of the tractor and trailer in motion, under these conditions, suction created in the manifold of the engine is distributed through the piping system to the vacuum operated motors I8 and 90 so as to maintain the pistons of the motors suspended in vacuum.

When the tractor and trailer are ascending an incline and it is desired to stop, the operator depresses the brake pedal .lever 48 to apply the brakes, and substantially simultaneously therewith the operator also depresses the clutch pedal -lever 50 to release the clutch. During the initial movement of the brake pedal lever 48, the control valve 54 is actuated to shut off communication between the conduit I0 and the conduit I02 and to open the conduit I02 to the atmosphere.

This results in instantaneous actuation of the brakes connected to the motors.

Upon opening the conduit I02 to the atmosphere, air entering the conduit passes through the electrically controlled valve I04 to the motor I8 back of the piston therein and also through the conduit I I8 to the relay valve I20, causing actuation of the relay valve resulting in closing tracted position by conventional the by-pass I22 and admitting air through the relay valve to the motor 90 back of the piston therein. I

Upon the admission of air into the motors I and 90, the suction created in the manifold of the engine and distributed through the conduit I0 and the branch conduits I4 and I6 to the motors causes instantaneous actuation of the motors during the initial movement of the clutch pedal lever 50;

As the motors I8 and 90 actuate the brakes they also, by means of rod 46, force casing 56 of valve 54 to the left, thus tending to bring piston 64 back into the same position relative to the casing 56 which it had before th start of the braking operation. Further pressure on the brake pedal 46 will therefore be necessary to .keep opening 00 connected with the atmosphere to continue applying the brakes.

As the clutch pedal lever 50- completes its stroke sufiiciently to release the clutch, the contactor IIB carried thereby engages the contact H4. The gravity switch IIZ having been previously closed due to the inclined position of the tractor on which the switch is mounted, actuation of the clutch pedal lever closes the circuit I08, causing energization of the solenoid I06, resulting in closing of the valve I04 and trapping of air in the conduits between the motor 18 and the relay valve I20 so as to maintain the brakes in applied position.

When the brake pedal 48 is released, the piston means for continuing the actuation of the brakes including vacuum actuated motors connected to the power plant of the vehicle and to the me-' chanical linkage, means for introducing air into the motors, and means for trapping air in the motors including an electrically actuated valve controlled by a gravity switch and a mechanically actuated switch.

3; In a vacuumbrake system for automobiles, the combination of brake actuating means, a power cylinder for controlling said means, means comprising a control valve for controlling flow of fluid to said cylinder to apply said brake and from said cylinder to release said brake, a fluid conduit for connecting said last-named means and said cylinder, a valve interposed in said conduit comprising a valve seat, an electrically operated valve element and a solenoid operableto move said valve element to said seat to close the valve to prevent flow of fluid and to hold I unit, a valve comprising an annular valve seat 64 will be moved back to its original position, thus opening port 60 to the source of vacuum.

At the conclusion of a braking operation, the operator shifts the transmission of the tractor, as in general practice, and slowly releases the clutch pedal lever 50 so as to engage the clutch. Upon release of the clutch pedal lever, a conventional retractile spring returns the lever to its normal position, and as the lever moves to its normal position the contactor I I6 carried thereby disengages the contact H4 and thereby opens the circuit I08. This results in de-energization of the solenoid I06 and opening of the valve I04 so as to establish communication between the manifold 68 of the engine and the motors l0 and 90. The pistons of the motors I8 and 90 are now suspended in vacuum, and under this condition the brakes are moved .to the off or reretractile springs.

Although this invention has been described in connection with certain specific embodiments, the principles involved are susceptible of numerous other applications that will readily occur to persons skilled in the art. The invention is, therefore, to be limited onlybythe'scope'of the appended claims. m

Having thus described the various features 'of the invention, what I claim as new and desire to secure by Letters Patent is:

1. A braking system for a motor vehicle h'aving separate control means for the electrically actuated means operated by movement of the pedal.

2. A braking system for a motor vehicle comprising mechanical linkage for initially and directly actuating the brakes of the vehicle, power and a valve element interposed in said means between said unit and said device, an electrically actuated valve stem secured to said valve element, and a solenoid operable to force said valve element into engagement with said seat, said valve element having a larger area facing toward said fluid pressure-supplying device than toward the said brake unit.

5. In a brake system for automobiles, the combination of means for directly actuating the,

bination of brake actuating means, a vacuumoperated power cylinder for controlling said means, valve means for controlling flow of fluid to and from said cylinder, a fluid conduit for connecting said valve means and said cylinder, a valve' interposed in said conduit comprising a valve seat, an electrically operated valve element, and a solenoid operabl to move said valve element to said seat to close the valve to prevent flow of fluid and to hold the brake applied.

7. A braking system for a motor vehicle comprising power means for actuating the brakes, electrically actuated means controlling the power means, a gravity switch for controlling the electrically actuated means and a separate switch for controlling the electrically actuated means.

8. A braking system for a motor vehicle comprising mechanical linkage for actuating the brakes of the vehicle, power means for actuating the mechanical linkage, including vacuum actuated motors connected to the power plant of the vehicle and to the mechanical linkage, means for varying the pressure in the said motors, and means for isolating the motors so as to maintain a difierential pressure therein, said last-named 

